Preservative and marine growth arresting process



iii

this??? PRESERVATIVE AND MARINE GROWTH ARRESTING PROCESS Wallace '11.Conn, Lawrence,' Mass, assignor to Government of the United States,represented by the Secretary of Commerce No Drawing. Application April5, 1934, Serial No. 719,180

3 Claims.

(Granted under the act of March 3, 1883,. as amended April 30, 1928; 3700. G. 757) The invention described herein may be manu- 1 factured andused by or for the Government of the United States for governmentalpurposes only, without the payment of any royalty thereon.

This is a continuation in part of my application Serial No. 640,352,filed October 29, 1932,

for preservative and marine growth arresting process, and relates to aprocess for the preservation of articles made of cellulose or fibrousmaterials and also for arresting marine growth by ti use of an organiccompound of mercury.

It is well known that fish nets and marine cordage when exposed naturalbodies of water for a. considerable period of time are subjected l todeterioration which results in a loss of tensile strength. It is obviousthat any accumulations of vegetable growth or of barnacle -lilre formsof shell fish which tend to close the meshes of the fish net ofierincreased resistance of the flow of water through the net. The stressesdue to this increased resistance may be sufhcient to result in. thetearing loose of the net from its anchorage.

Marine growths which are attached to nets which are suspended fromstakes or buoys also produce extra stresses due to the gravity andresult in extraordinary strain and labor when a not has been handled.Small barnacles and other shell fish having sharp edges, when attachedto nets result in the injury to the hands of fishermen. In certainfishing waters fixed heavy nets have to be brought ashore at frequentintervals for cleaning; this results in considerable cost andinconvenience. Itis obvious that any method or chemical process thatmaterially reduces marine growth and at the same time does not produceundesirable effects, is of commercial 1 value.

I am aware that considerable study of the demospheric changes, and hasdistinct advantages over that disclosed in prior publications andfurther is such a process as can be utilized for treat ing such fiberson a large commercial scale.

I am also aware, as taught by British Patent- Number 305,943 of 1930,that it has heretofore been known to treat wood 'by the application ofa'medium comprising, as an active ingredient,

a mercurized aliphatic hydrocarbon and to treat wood with a mediumcomprising, as an active compound, ethyl mercuric bromide dissolved into known.

search nggm an organic solvent such as tar. However, ithas notheretofore been known to treat marine cord-j age and the like with thecompounds. and by the method herein described and claimed.

My invention provides a preservative chemical treatment for fibrousmaterial, including fish nets, marine cordage and the like, as well asproviding an anti-fouling coating for the surfaces normally immersed innatural bodies of water for considerable periods of time. It has beenshown by actual tests to increase the resistance to the destructivegrowths and forces to which such nets are subjected when in use as wellmaterially reducing the accumulations oi marine growths on nets as wellas upon surfaces upon which the accumulations of marine growths areobjectionable.

It-has been found that inorganic compounds of mercury, for examplemercuric oxide, produce results of limited and uncertain values forpreservatives.

I have discovered that when an organiccompound of mercury containing anethyl radical, such as ethyl mercury oleate, ethyl mercury phosphate,and the like is mixed with or dissolved in. a suitable carrier, such asa tar-like substance, and applied to cordage or webbing, that the amountof depreciation of the tensile strength of the fish nets immersed innatural bodies of water is materially decreased; that the rate of thisdepreciation is reduced; and that the accumulations of marine growthsupon the nets are greatly reduced; thus the useful life of such nets ismaterially increased by lessening the maximum stresses to which they maybe subjected as well as prolonging the period during which the netretains sufiicient strength to be serviceable.

In fish net twine, to which this invention has been applied, it wasfound that a proportion of ethyl mercury oleate or ethyl mercuryphosphate equivalent in weight to 1/100% of the tar carrier waspositively but not materially elficacious, but when the proportion ofthe mercury compound was raised to A;%, the effect in reducing marinegrowths was superior to anything hither- Coincident with thisanti-fouling propertyof the organic mercury compound, thetensile'strength of the impregnated twine has a greater resistance todepreciation when exposed under adverse conditions, to a degree higl'ierthan has previously been found when natural.

cotton twine was impregnated with a mixture of tar and added chemical.

In the application of my pres'ervation I have found that bestresultsmaybe obtained by thoroughly mixing the organic compound with the tar,or similarcarrier, and immersing the cellulose material in this mixturefor a period of time sufficient in length to expel the air from thecellulose stock, which is approximately three minutes, at a temperaturesufficiently high to bring a thorough impregnation. A temperature ofmore than 180 F. has been found to give best results. The material thustreated should preferably be allowed to dry at atmospheric temperaturesbefore use.

Marine growths and depreciation of fish nets, cordage, and the like, aresubject to considerable variations due to location, month, year, etc.Hence, the protective requirement varies accordingly and, therefore, Ido not limit my invention to the percentage or proportion of organiccompounds of mercury having a radical such as ethyl mercury oleate orethyl mercury phosphate above described as efficacious, nor do I limitmy invention to this particular chemical in combination, since theefiectsf or benefits produced are due to mercury in organic combinationdisseminated g through or mixed with a carrier, with the mixture Myinvention also provides a means tor-materially retarding thedeterioration of canvas; tobacco cloth; cordage; twine; or the like,from the efiects of the weather and particularly from the effects ofrepeated wetting and long exposures in the air while damp.

The foregoing description comprehends only a general and preferredembodiment of my invention and detailed changes in the process, method,and compositions may be made within the scope of my claims which are,therefore, intended as not restricted to the specific details of myinvention as disclosed herein.

What I claim is:

1. Cordage and the like having combined therewith a flexible, adhesive,organic substance in combination with an organic compound of mercuryhaving an ethyl radical.

2. Cordage and the like having combined therewith ethyl mercury oleatein combination with a tar-like carrier.

3. Cordage and the like having combined therewith ethyl mercuryphosphate in combination with a tar-like carrier.

WALLACE T. CONN.

